An early-morning 40-vehicle pileup on westbound Interstate 10 in eastern New Orleans left two men dead and sent 25 people, including a firefighter, to the hospital to be treated for injuries while crews worked for hours to clear a tangle of cars, trucks and 18-wheelers that kept the highway closed for most of the day Thursday.

Police shut down lanes in both directions after the accident, causing New Orleans-bound traffic on the twin spans to back up to the north shore during the morning commute. Eastbound lanes reopened about 3:30 p.m.; westbound lanes reopened about 5 p.m.

It was the second time in two weeks that the interstate was shut down in both directions because of a fatal accident. A hit-and-run accident Dec. 17 near the City Park Avenue exit in Mid-City left 48-year-old Mitchell Baptiste dead and forced the closure of the highway for hours while police cleared the scene. No arrests have been made.

While the cause of Thursday's accident remains under investigation, the roadway was under a thick blanket of fog when the accident occurred about 4 a.m. near the Michoud Boulevard exit. The National Weather Service issued a fog alert Thursday morning warning of visibility as low as half a mile, particularly along I-10 in the east.

Some of those involved in the accident said driving conditions were especially challenging because the stretch of I-10 between Irish Bayou and Little Woods has lacked working streetlights the last several months.

Ryan Berni, a spokesman for Mayor Mitch Landrieu, said the lights between Interstate 510 and Michoud were repaired in July, although he said he could not say whether they were working Thursday morning.

City Councilman Jon Johnson, who represents eastern New Orleans, said he had not had any recent complaints about streetlight problems in that area.

Still, witnesses described an eerily dark scene, in which all they could see were headlight beams that tried to cut through the fog, and all they could hear were vehicles crashing into one another as people screamed and cried for help.

"It was boom, boom, boom," said Clarence Richardson, 38, of Slidell, who was driving in to begin his day as the executive steward at the Sheraton New Orleans when he saw the "domino effect" collisions.

"You could not see an arm's length in front of you," said Tyrone Yancy, 45, who was driving from Slidell. "Everything happened so fast."

He saw a car stopped in the middle lane and swerved to avoid it, but despite his efforts to miss hitting any other vehicles, his truck slammed into an 18-wheeler and spun around before coming to a stop.

He then sprinted across the flowing lanes of eastbound traffic and hid behind a guard rail until he heard the screams of a child and two adults.

He and several other people found their way to a black sport-utility vehicle that wound up under the back of a tractor-trailer.

Dwestly Ratcliff, 42, a tow-truck driver from eastern New Orleans, arrived on the scene after a client involved in the accident called to tell him about it.

Ratcliff also heard the screams amid the crashes but said he and others' efforts to rescue the three occupants of the mangled SUV were fruitless because of the car's splintered condition and location under the trailer.

"We couldn't do nothing, and that's the hurting part. We couldn't help nobody," Ratcliff said. "I get sick thinking about it. ... A bunch of grown men and we couldn't do nothing."

Killed in the crash was Michael Wall, 54, of Springfield, who rode with two other people, said John Gagliano, the Orleans Parish coroner's chief investigator.

Separately, Lloyd Williams Jr., 55, of Slidell died when the truck he drove was crushed between two 18-wheelers, Gagliano said.

Attempts to contact relatives were unsuccessful Thursday.

Twenty-five people were brought to the hospital to be treated for minor to critical injuries, said officer Garry Flot, a Police Department spokesman. A firefighter was treated and released from a hospital after he was cut on the face while trying to extricate someone from a vehicle, Flot said.

As day broke, the scope of the wreckage was revealed. It included several smaller pileups that included cars and trucks pinned between and below 18-wheelers, and one tractor-trailer cab that was impaled by a large pole it towed. That truck's driver escaped by climbing out the back of his cab and crawling out the hollow pole, witnesses said.

The roof of another vehicle, sliced off by first responders, was tossed on the neutral ground amid shattered glass, other vehicle parts and other miscellaneous items. The reek of fuel and smoke, reminiscent of the marsh fire that burned nearby for much of the summer and continues to smolder, filled the air.

Those who survived unharmed said they were more than lucky.

"It's a blessing to walk away," Richardson said. "No cuts or no scratches? That's a blessing."